1. Field of the Invention
The present invention relates generally to means for connecting microelectronic devices and systems. More particularly, the invention relates to improved flex-circuit based interconnect solutions for electronic circuits.
2. Description of Related Art
The evolution of smaller, lighter electronic devices with ever-increasing functionalities has increased the need for packaging, mounting, and interconnection architectures that will reduce size and weight while at the same time preserving interconnection characteristics that can handle the flow of large amounts of data between various circuits or modules in a device. Flex circuits are often used to provide a signal routing means that can be easily located in confined places within an equipment enclosure. They are also used to maintain electrical connections between two components that must move relative to one another; examples are the connections between the motherboard and the display on a laptop computer, or in many cell phones.
Various approaches have been used to enable a long, flexible circuit to be reliably connected to a component such as a motherboard. In one case, a socket is permanently installed on the motherboard (typically by soldering). A mating plug is affixed to the end of the flex by mechanically clamping or crimping; this plug contains internal metal pins that pierce the flex to complete an electrical connection between the lines on the flex and the contacts on the plug that will mate with corresponding contacts on the socket. As the number of lines increases, and the pitch becomes correspondingly smaller, both the cost and reliability of this approach can suffer.
Another approach, used particularly when the flex connection might need to withstand especially demanding mechanical forces, is to affix rigid circuit boards on both sides of the flex near the terminations. These boards typically have plated through holes and can be placed flat against the motherboard to secure a strong soldered connection. Connectors may also be further strengthened by potting in epoxy.
Objects and Advantages
Objects of the present invention include at least the following: providing a flex circuit board and interconnect system having reduced size and complexity; providing a low-cost, highly reliable flex circuit board or module and associated interconnect system; providing a more reliable and manufacturable flex circuit board or module suitable for directly mounting on a motherboard without additional packaging; providing a motherboard with flex circuit boards mounted thereon via a compliant interconnect; and, providing a method for manufacturing flex circuits that is cost effective and suitable for mounting directly on a motherboard without a separate socket.